Microfiche reader printer having multi-format capabilities

ABSTRACT

The microfiche reader printer has multiple format capabilities. A lens support holding one lens for each format is slidable to position a lens into the light path. Positioning of the lens support closes or opens switches which direct a logic circuit to cause a controller to drive the microfiche holding platen in a certain manner dependent on the format. Copying utilizes a rotating xerographic drum. The platen is driven by stepper motors having a digitized sinusoidal input for microstepping drive for constant velocity drive during copying where the movements of the platen and the drum must be coordinated. The platen also takes a half frame back step before printing so that it can accelerate forward over the half step forward to reach constant velocity during scanning of the frame.

BACKGROUND OF THE INVENTION

This invention relates in general to microfiche reader printers andspecifically to microfiche reader printers having multiple formatcapabilities.

Microfiche reader printers vary in complexity. In the most simple, theoperator manually moves the platen holding the microfiche to a locationwhere the correct frame is projected in a viewing screen. A pointer maybe connected to the platen, and a frame guide may be printed below thepointer so that the operator can locate desired frames easier. After thedesired frame is located, the magnified image is reflected to a printerwhere it is printed, often on sensitized paper.

More complex reader printers have automatic addressing so that manualsearching for the desired frame is eliminated. In these systems, themicrofiche is inserted into the platen in a set orientation, and themachine moves the platen a specific distance from an indexing locationto the desired frame. Two stepping motors, one for the x and ycoordinates are employed, and the distance between frames can betranslated into a number of steps for stepping motors. Many of thesemachines only have the capability of making a single print.

Still more complex reader printers are substantially more automated.Such machines may be programmed to copy automatically a series offrames. After the operator positions the microfiche and selects thecorrect printing sequence, the machine automatically moves the platenand microfiche from frame to frame and copies each frame. These machinesfrequently operate at high speeds and use xerographic printing toaccommodate the higher speeds.

A number of problems have been recognized in reader printers, and it isan object of the present invention to disclose and provide solutions tothe problems. The first relates to multiple formats. If a reader printeris owned by a document storage company, its customers may store data onmicrofiches of different formats. Even a single company may usedifferent formats for data of different sizes.

Microfiche is generally of standard size 148.75 mm (5.86 in)×105 mm(4.13 in), but microfiche is produced in nine different formatsstandardized by the National Microfilm Association. The following sevenformats are most frequently used.

    __________________________________________________________________________               VERTICAL                                                                             HORIZ NO. NO.                                                                              BLOWBACK                                                                              BLOWBACK                               FORMAT                                                                              MODE SPACING                                                                              SPACING                                                                             ROW COL                                                                              RATIO   % FULL                                 __________________________________________________________________________     2463 CINE 12.5 mm                                                                              15.5 mm                                                                             7   9  17      70                                      2060 COMIC                                                                              16.5   11.75 5   12 18      90                                      2498 COMIC                                                                              12.5   10    7   14 21.5    90                                     42208 CINE 7      8.75  14  16 30      70                                     42325 COMIC                                                                              7      5.5   13  25 38      90                                     48270 CINE 6.25   7     15  18 34      70                                     48420 COMIC                                                                              6.25   5     15  28 43      90                                     __________________________________________________________________________

The CINE mode produces sequential pages along a column top to bottom,and the COMIC mode produces sequential pages along a row left to right.The first two numbers of the format indicate the magnification neededfor full blowback and the remaining numbers indicate the number offrames. Thus, format 2498 is magnified by 24 power, and it contains 98frames. By blowing back less than 100%, the machine compensates forpositional inaccuracies and for failure for the frame size to havedimensions exactly proportional to the 81/2 in×11 in (216 mm×279.4 mm)copy.

If an automatic reader printer is designed for multiple formatmicrofiche, certain problems are created. The first relates to indexing.If frames are of different sizes, then corresponding frame indexes willyield different positions on different format microfiche. For example,in format 2060, a command to index to the fifth row and twelfth columnwould index the machine to the frame at the lower right corner of themicrofiche. If format 48420 were used, the same command directs thereader printer to a frame near the middle of the microfiche.

Multiple format readers have been previously provided. One such readeris the Bruning Model 97 reader manufactured by the assignee herein. Ithas two lenses for different magnifications, and switching from one lensto the other modifies the controller to compensate for the differentframe locations on different format microfiche. In the Model 97,switching between the two lenses modifies the control circuit whichcontrols the motors which drive the platen to the correct location. TheModel 97 is not a printer, however, and printing creates its own set ofproblems.

The problems are minimal if printing is done on a stationaryphotoreceptive medium with the image of the entire frame being projectedto the entire stationary photoreceptive medium. However, such copiersare inherently slow, and a higher speed copier requires scanning of theframe and projecting the scanned portion to a moving photoreceptivemedium. The immediately adjacent frame areas are projected toimmediately adjacent areas on the photoreceptive surface so that theentire frame is ultimately projected to the moving photoreceptivemedium. The present invention uses a rotating xerographic drum, butxerographic or photographic belts could also be used.

There must be coordination between the movement of the frame in the pathof the light and the rotation of the xerographic drum. New formatschange the relationship. For example, with format 2060 microfiche, theframe must be scanned horizontally 11.75 mm each time the xerographicdrum rotates once, but the horizontal scan of format 48420 is only 5 mm.Therefore, unless the horizontal scanning speed of the frame ofmicrofiche is modified with respect to the rotation of the xerographicdrum, the copying will be incorrect.

Another problem relates to maintaining constant velocity duringscanning. Stepper motors, which are used to drive the platen holding themicrofiche, do not have constant velocity drive between steps. Certainprior art devices use synchronous motors to drive the platen duringscanning. As successive windings are energized, the torque on the rotorvaries as the rotor moves between winding. This produces a somewhatjerky motion for the platen. Although these jerks are small, they resultin unclear copies.

The stepper motor also has difficulty accelerating the platen. If thescan starts at the beginning of a frame, the platen will be moving at anincreasing velocity at the beginning of the frame, have constantvelocity over the center of the frame and moving at decreasing velocityat the end of the frame.

Other problems relate to the magnification itself. Formats of differentmagnifications will need lenses of different magnifications, and thechosen lens will have to be moved into and out of the light path.Because of the high degree of magnification required, there is anextremely small depth of focus. Therefore, the distance from the filmplane to the focused lens must remain constant as the machine moves fromframe to frame. If not, as the machine automatically proceeded from thelower right frame to the upper left frame, the images of certain framesmay be out of focus. Because such machines are intended to besubstantially automatic, the operator cannot continually check on thefocus of intermediate frames. The problems are greater with multiplelenses because the play necessary to allow movement of different lensesinto the light path may create inaccuracies in positioning the lens.

In the prior art, one of the ways of maintaining the position of thelens with respect to the film surface was to carry the lens in a brassholder and rest the holder on the glass platen. Moving the platenbeneath the lens, therefore, would not affect the distance from themicrofiche to the focused lens. Resting the brass covers on the platencreates problems. In the present invention, the printer is below theplaten so that the lenses must be mounted below the platen. The brasscan also scratch the glass platen.

Simplicity of operation is also a concern. It is more complicated, forexample, to require an operator to choose a particular lens for theformat and then to have the operator also be required to set controlscorresponding to the format for scan rate and indexing. Ideally, themachine would automatically switch indexing and scan when a new lens ischosen.

Focusing is also a concern. Each time a lens is chosen, it will have tobe focused, and it is preferable to do the focusing mechanically ratherthan manually. The normal way of focusing these lenses is to merely movethem toward or away from the film plane. Such movement can beaccomplished by gears tied into motors.

It is uneconomical, however, to have a motor for each lens, and it isdesirable to have a single motor focus all lenses. Because the focus ofthe lenses that are not being immediately used is unimportant, thefocusing motor can move all three lenses simultaneously until the lensbeing used is in focus. Positive drive between the lenses and the motoris not desirable. if the lens reaches its fullest travel, the lens willstop the motor. In order to avoid damage to the motor, an expensiveclutch may be necessary. Separate controls will also be required.Therefore, it would be desirable if continued motor rotationreciprocated the lens.

Microfiche is produced in standard formats, but careless operators andworn machines can produce microfiche that does not conform tospecifications. For example, assume that in one format having 10 framesin the y direction the nominal distance between outermost frames is 140mm. If the platen has positioned one of the outermost frames in thelight path, a command to move 140 mm in the y direction would positionthe other outermost frame in the light path. Actually, in the presentinvention, the command would be to move a certain number of steps, andthe distance between outermost frames would be stored as a number ofsteps.

If the outermost frames are only 135 mm apart, if the first frame isaligned, a command to move to the other frame will result in missing theframe by 5 mm. In slower reader printers where each frame is viewedbefore printing, and the operator centers each image before printing,the problem is avoided, but where printing of frames are automaticallysequenced, the operator offers little or no manual control.

The alignment problem is further complicated if the rows in the COMICmode or columns in the CINE mode are skewed. In the COMIC mode, ifmovement along the y axis does not have compensating x correction, eachsuccessive frame will be incorrectly positioned either upward ordownward.

As was previously stated, the object of the present invention is todisclose and provide a reader printer and a method of reading andprinting microfiche that solves many of the problems of the prior art.In the foregoing description, a number of other problems are alsomentioned, and it is an object to this invention to disclose and providea reader printer that solves the problems.

SUMMARY OF THE INVENTION

One portion of the present invention relates to the mounting means forthe lens. Mounting means includes a pair of parallel gibs. A lenssupport in which the lenses are mounted is slidably mounted between thegibs whereby sliding the lens support positions a chosen lens in thelight path from the light source and microfiche to the copier. A landarea is on each gib, and the platen rests on the land areas. because thefocused lens is secured in the lens support, because the lens support isfixed (except for sliding) between the gibs and because the platen isfixed vertically to the land areas which are fixed to the gibs, thedistance between the platen and the focused lens is maintained constant.

Another part of the present invention includes the unique focusingmeans. In the present invention, the lenses are arranged in a straightline and all lenses are focused simultaneously. Focusing is accomplishedby moving the lens in the lens support toward or away from the platen.The focusing means comprises a pin extending outwardly from each lens.An eccentric shaft extends under each pin for supporting the pins andthe lenses at distance from the platen. A focus motor rotates theeccentric shaft and the eccentricity raises and lowers the pins and thelenses with respect to the platen.

Another feature of the present invention is the control means. When thelens support slides between the gibs and a lens is positioned in thelight path, a sensing means in the form of switches senses the positionof the lens support. The switches signal the control means to adjust theplaten drives for different frame-to-frame movements and for adjustingthe speed at which the platen moves to scan the frame being copied tocompensate for different microfiche formats.

Specifically, the circuitry provides for one branch for each lens andfor each format, and the sensing means selects the format for the lensposition in the light path. The format data and platen speeds duringcopying for each format are stored in memory, and each branch has aswitch that directs the branch, when activated, to the portion of thememory containing the format data relating to the format for thatbranch. Each branch also has a speed adjustment switch for fine tuningthe platen speed during copying for that branch. This accommodatesformat variations.

The present invention also utilizes a digitized sine wave to cause thestepper motors to approximate AC motors to obtain constant velocity.This is done by varying the voltage to adjacent motor windings bychanging the digital current input to the motor windings. As the voltageto one winding gradually increases, the voltage to the second windinggradually decreases giving a more uniform torque curve.

Because the velocity of the platen changes during acceleration, thepresent invention steps the platen backward approximately 1/2 frame andthen reverses the motor to accelerate back over that half frame.Therefore, when the frame being copied reaches the light path, theplaten is moving at constant speed. Deceleration takes place overapproximately 1/4 of the subsequent frame. As copying continues, thisprocess of backward motion preceding acceleration and forward constantvelocity motion continues from frame to frame across the microfiche.

In order to solve the alignment problem, the machine computes an averagedistance between frames. Stored in memory is the nominal distancebetween the outermost frames. Upon initiation of the align sequence, anindexing frame is viewed. The indexing frame is an outermost frame. Bymeans of verniers which are connected to the stepping motors, the platenis moved slightly to center the image in the viewing screen. Next, theplaten is moved in the y direction to the opposing outermost frame, andit is again centered by means of the vernier controls. A first yadjustment factor is computed by counting the number of steps necessaryin the y direction to affect adjustment and dividing that by the numberof frames in the row minus 1 which yields an average error betweenframes. The same procedures takes place upon x movements. Thereafter, inmoving from frame to frame, the controller adds the adjustment factor toeach move. In order to correct for skewing, there are two sets ofadjustments for each coordinate. The two y adjustments correct improperspacing during moves in the y direction and improper alignment duringmoves in the x direction. The x adjustment works similarly.

The methods of the present invention include the method of modifying themovement of the microfiche during scanning and during movement tosuccessive frames in accordance with the lens, which was chosen withregard to the format, the alignment method and the scanning method.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of the reader printer of the present inventionwith the front doors open exposing some of the internal parts.

FIG. 2 is a side view of the reader printer of the present inventionwith the top cover open.

FIG. 3 is a schematic of the copier portion of the reader printer of thepresent invention.

FIG. 4 is a plan view partially in section showing the detail of theplaten, the means for moving the platen, the lens support, and theviewing screen.

FIG. 5 is a plan view, partially cut away of the lens support of thepresent invention.

FIG. 6 is a front view of the lens support of the present invention.

FIG. 7 is a sectional view of the lens support of the present inventiontaken through plane VII--VII of FIG. 6.

FIG. 8 is a bottom view of a portion of the platen moving means.

FIG. 9 is a side view of a portion of the platen moving means takenthrough plane IX--IX of FIG. 4.

FIG. 10 is a view of the control panel of the present invention.

FIG. 11 is a schematic of the control means and its relationship to theplaten, the platen moving means and the lens support.

FIG. 12 is a flow chart for the align function.

FIG. 13 is a block diagram for the control circuit for the stepper motormoving the platen in the y direction.

FIG. 14 is a diagram illustrating the current waveform applied to the ystepper motor for each step during scanning.

FIG. 15 is a schematic diagram of the control circuitry for two phasesof the y stepper motor.

FIG. 16 is a schematic diagram of control circuitry for the x steppermotor.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Description of EntireMachine

FIGS. 1 and 2 show the entire machine. Briefly, the reader printer ofthe present invention comprises a base having a hinged cover 11 mountedthereon. Light source 14 (FIG. 2) includes a lamp mounted in lamphousing 15 which directs light to reflector 16 where it is directedthrough microfiche 21 (FIG. 3) mounted in platen 20. By means of opticalelements discussed hereinafter, the image from the microfiche is eitherdirected to view screen 18 or xerographic drum 22.

The optical system operates as follows. Light from source 14 is directedthrough microfiche 21 (FIG. 3) which is held in place by movable platen20. Magnifying means in the form of lens 26 receives an image from themicrofiche and magnifies the image. As discussed in more detailhereinafter, lens 26 is chosen from a plurality of lenses mounted on alens support which allows one of the plurality of lenses to be movedinto the light path. From the magnifying lens 26 the image is directedto mirror 29. In the position shown in solid in FIG. 3, the image frommirror 29 is reflected to mirror 30 where it is again reflected to drum22. Alternatively, mirror 29 can be pivoted to its phantom positionwhere the image is reflected to viewing screen 18. Because of theshorter distance between magnifying lens 26 and viewing screen 18 thanbetween magnifying lens 26 and drum 22, a diopter lens 31 ispositionable in the light path to shorten the focus. It is operablyconnected to mirror 29 so that when the mirror pivots to reflect theimage to view screen 18, the diopter lens 31 is automatically positionedin the light path.

It will be recognized that many other optical systems are possible.Instead of having mirror 29 pivot, for example, a mirror could bemovable into and out of the light path to selectively direct the imageto the view screen.

The copier of the present invention utilizes an electrostatic dryprocess in which selenium drum 22 is first given a positive charge bycorona 36. The drum is then exposed to the image. The positive charge onthe drum surface is dissipated in relation to the intensity of thelight. The positive charge remaining on the drum surface forms thelatent image. Relatively negative toner particles are applied to thedrum from toner supply container 38 by means of a magnetic brush 37. Thepositively charged latent image attracts the toner to form a visibleimage. The image is transferred to a sheet of copy paper 39 as it passesover negative DC transfer corona 40. The negative charge of the transfercorona is greater than the positive charge of the drum. Therefore,because the drawing effect of the corona overcomes the holding effect ofthe drum, the image is transferred to copy paper 39. Any chargeremaining on the drum surface is neutralized as it passes an AC corona41. Any remaining toner is brushed off the drum by brush 42 and is thenvacuumed into a disposable bag 43. Copy paper 39 passes through fuserrollers where it is directed to holding tray 45. Tray 45 may be providedwith a sensor 46 to warn the operator or shut off the machine when tray45 is too full.

Some of the parts discussed in FIG. 3 are shown in their true locationin the machine in FIG. 1. For example, toner supply 38 is shown in FIG.1 and is accessible to the operator so that he can add toner. Seleniumdrum 22 is also visible for cleaning and other maintenance. The tonerdisposing container 43 also has access to the front of the machine sothat excess toner can be removed, and a portion of fuser 44 is alsoaccessible.

The Lens Support

The lens support of the preferred embodiment is shown in FIGS. 5, 6 and7. In the exemplary embodiment, lens support 25 holds three lenses, 26,27 and 28. Three lenses were chosen in the exemplary embodiment for sizereasons. A larger machine could accommodate more lenses. However, manypersons who need multiple format capabilities only use three differentformats. With the teachings herein, one of ordinary skill in the artcould modify this device to use more than three lenses.

Mounting means are provided for mounting the lens support for movementto position one of the lenses in the light path. The mounting meanscomprises a pair of parallel gibs, and the lens support is slidablymounted between the gibs such that sliding the lens support between thegibs positions a chosen lens in the light path. In the exemplaryembodiment, the mounting means comprises a main frame 61 (FIG. 5). Upperand lower parallel gibs 62, 63 are securely mounted on the main frame.Each gib is machined and finished to high tolerance and is correctlypositioned and fastened to main frame 61 by screws 75.

Lens support 25 includes a lens board 64 attached to board frame 65(FIG. 7). The bottom of lens board 64 rests on main frame 61 and thefront and rear edges 73, 74 are held by the inner edges 71, 72 of gibs62 and 63 respectively. As shown in FIG. 7, edges 71 and 72 slantupwardly and inwardly corresponding to the slant of edges 73 and 74 tosecure lens board 64 against main frame 61. It is important that lensboard 64 be held securely, especially in the vertical direction, becauseany movement up or down will move lens 28 thereby taking the magnifiedimage from the microfiche out of focus.

The precision surface of edges 71, 72, 73 and 74 allows lens board 64 toslide along the parallel gibs thereby moving one of the lenses 26, 27 or28 into the light path.

Mounted to the rear of board frame 65 is bar 68 which has a plurality ofindentations 66 cut therein. Each indentation is centered with respectto one lens. A line extending down the page in FIG. 5 would pass throughthe center of the light path. A roller 67 is urged by a spring (notshown) to the left in FIG. 7 or downward in FIG. 5 into an indentationwhen a lens is correctly oriented in the light path so that the personmoving the lens will sense the correct position.

In order to assist the operator in moving lens support 25, a handle 76is attached to board frame 65 and extends in front of main frame 61where it can be reached by an operator. A pin 77 extends upward fromhandle 76 to the top of main frame 61 adjacent the pin. A set of indicia78 (FIG. 4) are mounted on the main frame near the pin. The indiciaindicate different microfiche formats, and the operator making a copy offrames of microfiche moves handle 76 to one of the three format indiciato move the correct lens corresponding to the magnification of theformat into the light path.

Lens Focusing

The reader printer of the present invention further comprises focusingmeans attached to each lens for adjusting the focus of each lenssimultaneously. It will be recognized, however, that because only onelens is in the light path at one time, the focus of the other two lensesis irrelevant. However, the single focusing means which moves all threelenses up and down simultaneously add simplicity to the presentinvention.

The lenses are mounted in a straight line, and focusing is accomplishedby moving the lens toward or away from the platen. The focusing meanscomprises a pin 84 fixed to lens 28. As pin 84 moves upward and downwardin FIG. 7, the lens will also move upward and downward. An eccentricshaft extends under each pin for supporting the pins and the lenses atdistances from the platen. In the exemplary embodiment, eccentric shaft82 extends between shaft supports 83 on either ends thereof (FIG. 5).One end of eccentric shaft 82 is eccentrically mounted to gearing 81 offocus motor 80. As focus motor 80 drives gearing 81, shaft 82 rotates.The eccentricity of the mounting of shaft 82 raises or lowers pins 84 toraise and lower the lenses thereby focusing the lens being used.

The correct focus is judged by the operator who attends to focusing whenthe image is projected to the view screen 18 (FIGS. 1 and 4). The"focus" buttons (FIG. 10) direct the motor to rotate the eccentric shaftin either the + or - directions (arbitrary), but it is recognized that asingle direction rotating shaft would suffice because the rotation willalways return the shaft to any desired position. Rotation in eitherdirection is preferred, however, because if the operator overshoots thecorrect focus, he or she can reverse the motor a short distance to reachthe correct focus.

Movement of the Platen

The vertical position of the platen must be held constant with respectto the focused lens if lens focusing is to be maintained. It should beremembered that the device is automatic so that once focusing of aparticular microfiche is accomplished, the platen will move sequentiallyto print different frames. Therefore, because of the distances traveledfrom one end of the microfiche to the other, focusing errors could begreatly magnified.

In order to maintain the distance between the platen and the focusedlens constant, the platen slides on a land area which is a part of eachgib 62 and 63. These land areas 69, 70 are of a precision finish so thatthe glass of the platen can slide along with minimum friction andwithout becoming scratched. Any precision finished metal would suffice,or the land areas may have a friction resisting surface. Normallubrication cannot be used, however, because the lubricant would dirtythe glass platen.

Throughout its movement, the platen rests on the land areas. Because theland areas are tied to the main frame 61 which is in turn tied to lenssupport 25 in a fixed relationship, the lens is maintained a fixeddistance from the platen throughout its entire movement. It will also benoted that the land areas 69 and 70 are immediately nearest the lens inthe light path so that the portion of the platen at which the distanceto the focused lens is critical is the area in which the criticaldistance is best maintained.

The platen is essentially moved by motors in two coordinates. The motorsoperate in a unique manner and the controls for the motors are alsounique. Explained in this section, however, are the mechanical movementsthat the motor accomplishes. Although somewhat unconventional, movementfrom left to right or right to left is signified in FIG. 4 as being inthe y direction while up and down movement in FIG. 4 is indicated as inthe x direction.

Movement of the platen in the y direction is accomplished by a steppermotor 90 which through gearing in gearbox 92 rotates drive pulley 93 toadvance cable 95, which also extends around idler pulley 94. The ends ofcable 95 are attached to a bracket 96 which is fixed to platen support23. Platen support 23 holds the glass portion of the platen 20. Part ofplaten support 23 extends around shaft 24 on which the platen slides.Rotation of pulley 93 by y motor 90 causes the cable to pull on bracket96 thereby pulling platen 20 in either the +y or -y directions. Bracket96 has a fitting for adjusting the tightness of cable 95.

X motor 91 operates in a similar manner. As shown in FIG. 8, motor 91 ismounted on gearbox 97. Through appropriate gearing, motor 91 drives xpulley 98 to advance cable 100 which extends around idler pulley 99.Both ends of cable 100 are attached to x bracket 101 which also hasfittings for adjusting the tightness of cable 100. Bracket 101 isattached to y motor bracket 102. As the x motor 91 causes pulley 98 torotate in either direction, the cable 100 pulls in either direction onbracket 101 which in turn pulls in either direction on y motor bracket102 and the entire assembly for y motor 90 including the gearbox and theassociated cables moves in the x direction (FIG. 4). Y motor bracket 102is also attached to shaft 24 so that as the y motor moves in the xdirection, platen 20 also moves in the x direction. By coordinating themovement from y motor 90 and x motor 91, platen 20 can be moved in the xand/or y direction to any desired position.

Scanning

As has previously been discussed, the movement of the frame ofmicrofiche through the right path is coordinated with the rotation ofthe drum. The present reader printer is designed to print on standardletter size paper (81/2"×11"), although it can be modified to print onother size paper. The paper is fed along the drum in a directionperpendicular to the long (11") side. Therefore, the microfiche must beoriented such that the direction of movement of the microfiche isperpendicular to the longer dimension of the frame. It should be notedthat the long frame dimension does not necessarily correspond to thelong side of the microfiche.

Microfiche in the COMIC mode is usually taken from letter size sourcedocuments. The long side of a frame is usually parallel to the shortside of the microfiche. The CINE format is usually used for copyingcomputer printouts and similar sized documents. In those, the longerdimension of each frame corresponds to the longer dimension of themicrofiche. When such a format is used, the microfiche must bepositioned in the platen such that the long edge of each frame andconsequently the long edge of the microfiche is parallel to the axis ofthe xerographic drum. Referring to FIG. 1, the microfiche must beoriented such that the long dimension of each frame is along the rightwall of platen 20.

Once the desired format is chosen, the viewer printer controllerindicates on controlled panel 50 the correct orientation of themicrofiche into the platen. This is shown at areas 110, 111, one ofwhich lights after the format is chosen (FIG. 10).

From the foregoing, it is recognized that the scan of the microfichealways proceeds perpendicular to the long edge of the frame.

It is difficult to coordinate the speed of the xerographic drum with theplaten movement. In a regular full size document copier, variations inthe scan rate are not critical, but slight variations in the platenspeed of a microfiche reader printer can result in illegible copies. Ifthe platen moves too fast, the information will be shrunk in a directionalong the short side of the paper. If the platen moves too slowly, theimage may overblow the copy paper. The difficulty of the problem is bestillustrated by remembering that for example with 48420 formatmicrofiche, where each frame has a 5 mm horizontal dimension, the copypaper will be moving 216 mm (8.5 in.). These problems are made moredifficult because of the multiple format capabilities of the presentmachine.

The scanning during printing is done only along the y axis. Movementalong the x axis only serves to position the microfiche to position aframe in the light path, a function that sometimes shares with y motor90. Both x motor 91 and y motor 90 are stepper motors which rotatethrough a series of steps as pulses are applied to the motor windings inorder. The electrical controls for the stepper motors 90 and 91 will bediscussed in detail hereinafter. Briefly, however, the controls providefor rapid, controlled acceleration for y motor 90.

The control means has computer input. Stored within the computer is thefollowing information reproduced in tabular form:

    __________________________________________________________________________    COMPUTER FORMAT DATA TABLE                                                               NO. NO.                                                                              STEPS/                                                                             STEPS/    COMIC                                                                              CLOSEST                                 FICHE                                                                              FORMAT                                                                              ROW COL                                                                              COL  ROW  DELAY                                                                              PREF FRAME                                   __________________________________________________________________________    1     2060 5   12 132  94   26   1    1, 6                                    2     2498 7   14 100  80   32   1    1, 7                                    3     2463 9    7 124  100  15   0    1, 5                                    4    42325 13  25 56   44   71   1    16,                                                                              11                                   5    42208 16  13 70   56   54   0    16,                                                                              10                                   6    48420 15  28 50   40   80   1    1, 14                                   7    48270 18  15 62   50   62   0    18,                                                                              10                                   __________________________________________________________________________

In the exemplary embodiments three formats can be chosen correspondingto the three lenses. This application will discuss hereinafter how theseformats are chosen. Assume, for example, that formats 2498, 42208 and48270 are chosen. The computer is programmed such that fiche type 2(format 2498) corresponds to a fiche having 7 rows and 14 columns.

Each step in the exemplary embodiment corresponds to a 1.8° revolutionof the motor. Thus, the motor rotates once per 100 steps. The gearingand pulleys translate the steps a distance of 32 steps/mm orapproximately 0.03 mm/step. The "stops per column" and "stops per row"are multipled by 4 (a 2 place binary shift) to yield the actual numberof steps. Based on the distance per step of stepper motors 90 and 91,the computer directs the motors to take 400 steps per column and 320steps per row. The "delay factor" is the speed at which the steps aremade. The computer also senses whether the COMIC mode or the CINE modeis preferred. A "1" in the "COMIC preferred" row indicates that theCOMIC format is preferred. The closest frame indicates the frame numberof the frame closest the upper right hand corner of the platen.

The actual scan speed may be faster than the nominal speed determined bythe "delay factor", to accommodate lenses of slightly different focallengths and nonstandard material on the frames. For example, format48420 moves only 5 mm, or 160 steps. Therefore, the processor signalsstepper motor 90 to step the motor 160 steps during the time that asingle sheet of copy paper passes through the copier.

Switches, separate from the computer, are adjusted depending on theformat used in a particular machine to adjust the speed upward. Byhaving separate adjustments switches, it is unnecessary to reprogram theprocessor for variations in lens and in the makeup of the frames. Forexample, if the original source material is made with very smallmargins, there may be insufficient tolerance during blow-back. The speedof the platen may have to be increased slightly to shrink the copy alongthe y axis. If the speed controls were only in the processor,reprogramming of the processor would be necessary, but by having thespeed control in accessible switches, it may be possible to increase theplaten speed in the y direction slightly. Also the focal length of thelens can be changed simultaneously with adjusting the speed ifoverblowing is a great problem.

As has previously been stated, motor control is obtained throughcontrolling the number and rate of pulses to the stepper motors. Thecontrol means must be signaled with the correct format information.Although the format change could be accomplished with separate switches,the present invention ties the format change to lens position. Thereason for that is that it ensures that the correct lens will bepositioned for a chosen format.

As shown in FIG. 5, if handle 76 attached to lens support 25 is moved tothe left, board frame 65 will contact switch 106 to close it. If lenssupport moves to its fully extent to the right, it contacts switch 107.In the exemplary embodiment, the switch is arranged such that focusmotor 80 actually contacts switch 107.

Referring now to FIG. 11, assume that the lens support 25 has closedswitch 106. This directs power to a select switch 108. There are threeselect switches which are in the form of dials. Depending on whichformats are chosen, the select switch will direct the processor to aparticular format routine. For example, if one of the formats is to be2498, a 24 power lens would be mounted in the rightmost opening of lenssupport 25. Select switch 108 would be in position No. 2 which, as shownin the preceding table, directs the processor to format 2498. Note thatwhen the rightmost lens 27 is in the light path, the lens support 25will be moved to its leftmost position closing switch 106. If format42208 microfiche is also to be copied, an approximately 42 power lenswould be positioned in the left opening of lens support 25. Selectswitch 109 is dialed to 5 which directs the processor to the format42208 routine. It will be noted that in the exemplary embodiment, thereis no third switch. The third format is sensed by an absence of signalsfrom switch 106 or 107. A logic circuit in the form of NOR gate 113signals when both switches 106 and 107 are open which thereby choosesselect switch 110 for the format choice. As an example, select switch110 could be dialed to 7 to choose format 48270, and the computer wouldbe directed to the routine for format 48270.

During scanning, the platen undergoes a novel movement. First, theacceleration is precisely controlled by controlling the current to thestepper motors. During the acceleration phase, additional torque issupplied by the motor to the platen. The manner in which the increasedacceleration is provided electrically is discussed hereinafter.

Another problem deals with acceleration while a portion of the frame isover the light path. If the platen is accelerating during copying, theimage will be blurred or compressed over the portion copied duringacceleration. Therefore, the present invention provides for reversingthe platen a short distance in a direction opposite the direction ofscan, reversing the motor again and allowing the platen to accelerate toits format velocity over the short distance. Under direction from thecontrol means, y stepping motor 90 then provides constant velocitymotion in the y direction to platen 20 over the number of stepsnecessary to scan a frame. For example, as shown in the computer formatdata table, if format 2498 is chosen, the y motor will advance 320(80×4) steps to traverse the frame at constant velocity. After scanningis complete, the platen decelerates over a portion of the next frame. Toinitiate copying of that frame, the platen must be reversed over thedistance of deceleration as well as the additional distance foracceleration.

As an example, assume that frames B8, B9 and B10 are to be copied. Thepresent machine is arranged to print the last frame first so that itappears on the bottom of the stack of copies. This greatly assists incollating copies. The control circuitry therefore directs the x and ymotors to position frame B10 in the light path. When printing isinitiated, the platen first moves a small distance to the left,approximately 1/2 frame so that the light path is through a portion offrame B11, the frame immediately to the right of frame B10. The y motorthen begins accelerating until the format speed is reached when orbefore the right-hand side of frame B10 enters the light path. The ymotor then rotates at constant speed moving the platen to the rightuntil the left-hand side of frame B10 passes through the light path. Themotor will then decelerate over a portion of adjacent frame B9. In theexemplary embodiment, the deceleration takes place over approximately1/4 of the adjacent frame. Thereafter, the platen would retreat again sothat the light path is approximately 1/2 of the way into frame B10, andthe platen would accelerate until the right edge of frame B9 passedthrough the light path. This process is repeated for all copying.

If more than one set of copies is desired, the machine continues torepeat its sequence. It is seen that the bottom copy emerging into tray45 will be frame B10 followed in order from the bottom by frames B9 andB8. The print is face up so that when the copies are removed from tray45, they will be in the order B8, B9 and B10 from top to bottom, thecorrect order. Additional sets of these copies would be fed on top ofthe first pile.

In contrast to the precision scanning movement required by the y motor,the speed of movement from frame to frame is not crucial, only thedistance (number of steps) is. Assume, once again, that the machine isset at the 2498 format and frame A1 is currently in the light path. Thelocation is stored in the processor. Assume further that the operatordesires to view frame D10. The processor computes that it will have tomove down three rows from row A to row D. As shown in the computerformat data table, x motor 91 must make 400 steps to traverse a columnframe. As there are three frames that must be traversed in the xdirection, the processor directs the x motor to move 1200 steps.Simultaneously, the y motor must move nine frames in the horizontaldirection from column 1 to column 10. Knowing that it has 320 stepsalong a row to traverse a frame, the processor calculates that the motormust turn through 2880 steps until it reaches the 10th column. Becausethe motors operate simultaneously during a portion of the travel, theinitial platen movement is diagonal followed by movement along the yaxis.

Alignment

The invention also has means for modifying the alignment between framesfrom standard or nominal alignment in order to accommodate variations inthe microfiche. These variations can take two forms, skewing andimproper spacing. The alignment means of the present invention operateson a principle such that the total deviation from one side of themicrofiche to the other is assumed to be constant. The total deviationis computed, and an average deviation is attributable to each frame.Thereafter, as the controller moves the platen between frames, theplaten is moved its nominal distance plus the deviation. It isrecognized that there could be a negative deviation, in which case, thecontroller is considered to add algebraically the negative deviation.

Alignment is accomplished in the following manner. After microfiche isloaded into the platen, the operator pushes the "view" button (FIG. 10).The machine automatically positions the upper left-hand frame in thelight path. Next, the operator presses the "align" button. Thisautomatically moves platen 20 to the left to position the upper rightframe in the light path. For convenience, reference can be had to themicrofiche shown in FIG. 11. The operator then determines if the frameis centered with respect to centering lines 19 on view screen 18. Ifnot, the operator can move the platen by means of x vernier keys 120activating the x stepper motor and y vernier keys 121 actuating the ystepper motor (FIG. 10).

The controller stores the number of steps moved in the y direction whichit uses to determine a correction factor indicated as YADJUST(1) in theflow chart of FIG. 12. The correction factor is determined by dividingthe number of y steps in the correction by one less than the number offrames per row. This factor then determines the portion of the errorattributable to each space between frames, and there is one less spacebetween frames than there are frames. YADJUST(1) is a factor that isused to correct for improper spacing between the frames.

Simultaneously, a factor XADJUST(1) is used to correct any angularmisalignment of the microfiche images with respect to the edge of thefilm. The operator adjusts the frame up and down by use of vernier keys120 and the number of steps taken by the y motor is determined. Thefactor XADJUST(1) is computed by dividing the number of steps made forthe adjustment in the x coordinate by one less than the number of framesper row.

The operator now presses the "align" button again, automatically movingthe platen inward to position the lower right frame in the viewingscreen. Once again, by means of vernier keys 120 and 121, the operatorcenters the image between centering lines 19. This computes a factorXADJUST(2), which is a correction factor for improper spacing in the xaxis. It is computed by dividing the number of steps taken by the xmotor during adjustment in the x direction and dividing it by one lessthan the number of frames per column. To compensate for angularmisplacement of the frames, factor YADJUST(2) is computed by dividingthe number of steps necessary to center the frame along the y axis anddividing that number by one less than the number of frames per column.Thereafter, the operator presses the "align" button again, and theplaten moves diagonally back to the initial position. If the operatorwishes, the alignment procedure can be done a second time for finetuning the alignment. The control means is programmed to change theXADJUST and YADJUST factors slightly for each iteration.

The use of the adjustment factors will be explained by way of thefollowing example. Assume that the microfiche has 10 frames across inthe y direction and 6 frames down in the x direction. Assume furtherthat that translates to 1000 x steps and 500 y steps. In making thefirst adjustment (XADJUST(1) and YADJUST(1)), the platen automaticallymoves the 1000 steps in the y direction. Assume further that in order tocenter the frame, the operator must rotate y motor 90 steps.YADJUST(1)=90/(10-1)=10. Assume further that the x motor had to move 45steps through the use of x vernier 120. XADJUST(1)=45/(10-1)=5.

When the "align" button is pressed a second time, the platen moves toposition the bottom right frame in the light path. Assume that the framehad to be moved 40 steps in the x direction and 30 steps in the ydirection. YADJUST(2) and XADJUST(2) are then computed;YADJUST(2)=30/(6-1)=6. XADJUST(2)=40/(6-1)=8.

Once the adjustment steps are completed, assume that the machine isasked to move from frame A1 to frame A3. This is accomplished bypressing first the key 121 marked "A" followed by keys "0" "3". Usingthe same assumptions above, such a move in the y direction wouldnormally take 200 y steps and no x steps. However, because of thecorrection factors, a two frame move will require 20 (10×2) additionalsteps. Therefore, a two frame y move will be 220 steps rather than 200steps. Likewise, instead of having no x component to the move, a twoframe y move will need a correction factor of 10 (5×2)× steps. If nextthe machine must move 4 frames in the x direction, the controller willautomatically move an additional 32 spaces (8×4). Instead of having noinput from the y motor, a move of 4 frames will require 24 y steps(6×4).

Frequently, all of the microfiche being copied at one time will havebeen produced on the same machine, and it may be unnecessary to repeatthe alignment routine for each microfiche. However, because of the easewith which alignment is accomplished, it is easy for one to align eachnew microfiche.

As shown in FIG. 10, the present invention has a "reset" button. Thisbutton must be activated to cause the controller to pick a new branchupon movement of the lens support. The reset control allows lesscomplicated circuitry to detect what lens is being used. Lens switches106, 107 do not have to be constantly monitored.

Motor Control Circuitry

FIG. 13 is a block diagram of the circuitry employed to implement motioncommands for the y direction motor as directed by the appropriateroutine corresponding to the selected format. Y motor 90 is a steppingmotor having four windings W1, W2, W3 and W4. The windings are disposedat successive 90° phase angles, and are divided into fifty segmentseach. While for simplification of description the operation of thecontrol circuit is described hereinafter as if stepping wereaccomplished in only four 90° steps per rotor revolution, it should beunderstood that because of the winding segmentation each step actuallyinvolves a rotation of 1.8°.

The torque developed by the motor at any time is determined by theamount of current flowing in the windings and the angular position ofthe rotor relative to the energized windings. While motor 90 could beoperated by successively energizing each of the windings in order, onewinding at a time, in the preferred embodiment an overlap betweensuccessive winding energizations is introduced to reduce or eliminate ajerking motion that would otherwise result from abrupt shifts betweenwindings. As described in detail below, the invention also contemplatesthe energization of individual windings with shaped current waveforms,rather than square waves with abrupt rise and fall characteristics, tofurther reduce jerking.

In the embodiment shown, energization of 180° opposed motor windings W1and W3 is controlled by one circuit, while energization of the other180° opposed motor windings W2 and W4 is controlled by a second circuitof similar design. The control circit for windings W1 and W3 comprises agroup of input terminals T1, T2, T3 and T4 adapted to receive binarycoded input signals from the controller, and connected through afiltering and isolating circuit 201 to a digital to analog converter(DAC) 202. A winding selector circuit 203 received the DAC output and isconnected in a first output circuit via output lead 204 and amplifier205 to winding W1, and in a second output circuit via output lead 206and amplifier 207 to winding W3. Only one of these two windings isenergized at any time, the appropriate winding being selected by windingselector circuit 203 in response to a signal from the controller. Aninput terminal T5 is provided to receive the controller signal andtransmit it through a filter and isolating circuit 208 to windingselector circuit 203.

An identical circuit is provided for control of windings W2 and W4.Input terminals T6, T7, T8 and T9 receive binary coded input signals,which signals are transmitted through filter and isolating circuit 209and converted to analog form by DAC 210. A winding selector circuit 211receives the output of DAC 210 and is provided with a first outputcircuit comprising output lead 212 and amplifier 213 connected towinding W2, and a second output circuit comprising output lead 214 andamplifier 215 connected to winding W4. Winding selection is controlledas in the first control circuit by a signal received at input terminalT10 and transmitted through a filter and isolating circuit 216 towinding selector circuit 211.

The general manner in which the motor windings are energized will now bedescribed. The magnitude of energizing current delivered to windings W1and W3 is determined by the pattern of input pulses received from thecontroller at input leads T1-T4. DAC 202 establishes a binaryrelationship among T1-T4, with T1 representing the least significant bitand T4 the most significant bit. The current delivered to windings W1and W3 is thus controlled by the pattern of signals at input terminalsT1-T4. Similarly, the current magnitude delivered to windings W2 and W4is controlled by the signal pattern at input terminals T6-T9.

Motor velocity is controlled by the rate at which energization isstepped from winding to winding, which in turn is controlled by theoscillation rate of the signals delivered to terminals T5 and T10.Assume first that a pattern of pulses is present at terminals T1-T4 butnot at terminals T6-T9, the rotor is aligned with W1, and the signal atterminal T5 is such that winding selector circuit 203 directs asenergizing signal to winding W1 but not to winding W2. A signal patternis then applied to terminals T6-T9, with the signal at terminal T10 suchthat winding selector circuit 211 causes winding W2 to be energized. Therotor begins to rotate toward a midpoint between W1 and W2, at whichpoint the energization of W1 is reduced below that of W2 and thenterminated so that the rotor continues rotating to an alignment with W2.In the next step winding W3 is energized by applying a new signalpattern to terminals T1-T4 and negating the signal at T5. Winding W4 isthen energized and winding W2 de-energized as the rotor passes windingW3 by terminating the signal pattern at T6- T9, applying a new signalpattern to T6-T9, and negating the signal at T10 such that windingselector circuit 211 now directs energizing current to windings W4.Finally, winding W1 is reenergized and winding W3 de-energized as therotor passes winding W4 by terminating the signal pattern at T1-T4,applying a new signal pattern to those terminals, and negating thesignal at T5 such that selector circuit 203 now directs current towinding W1.

To enhance smooth movement of its rotor and thereby improve the qualityof microfiche copies, the windings of y motor 90 are sequentiallyenergized with shaped current waveforms characterized by stepped risesand falls generally approximating a sine wave. Current waveforms forwindings W1-W4 are plotted against time in FIG. 14. Beginning at theleft hand side of the figure with a zero energization for W1, the signalpattern at terminals T1-T4 of FIG. 13 is sequenced through a series ofcombinations such that the current through W1 increases in a stepfashion to a peak at 217, and then decreases back to zero in asymmetrical step fashion.

The rotor is aligned with W1 concurrently with its peak energization217, at which time sequencing of a signal pattern commences at T6-T9 toproduce a similar energization waveform for W2. At the peak 218 of theW2 energization the W1 current has fallen to zero, the rotor is alignedwith W2, and a repeat of the sequenced signal pattern commences atT1-T4. At this time, however, the control signal established at T5 isnegated, causing energizing current to now commence flowing through W3rather than W1. The current through W3 likewise increases in stepfashion to a peak 219 at which time the rotor is aligned with W3, thecurrent through W2 had dropped to zero, application of a new signalpattern at T6-T9 begins, and the signal at T10 is negated to direct thenew energizing signals to W4 rather than W2. In the same manner thecurrent through W4 steps up to a peak 220 and then steps back to zero.

Successive current waveforms for W1-W4 are 90° out of phase with thewaveform for the previous winding. At cross-over points 221, 222, 223and 224 between successive waveforms the rotor is located equidistantlybetween the two energizing windings. The result is a preciselycontrolled motor movement that substantially eliminates jerking of ymotor 90 and resulting distortions in the final microfiche copy.

Y motor 90 rotates as the sequential energization of the motor windingsprogresses as described above. In the preferred embodiment the motor iscontrolled such that, after a lens has been aligned at the beginning ofa frame, y motor 90 is reversed and moves the microfiche card backwardsby a predetermined amount, such as one-quarter frame length. The motoris then accelerated in a controlled fashion so that, by the time thebeginning of the frame has again reached the lens, the platen is movingat or near full copying speed. Control over acceleration is achieved bycontrolling the buildup of motor velocity over the acceleration periodbefore the frame is reached. Motor velocity at any given time iscontrolled in turn by the frequency at which the signals at T5 and T10are alternated, and thus by the rate at which cyclic energization of thewindings proceeds. Initially, with the motor beginning at rest, thesignals at T5 and T10 are alternated at a relatively slow rate. Asacceleration progresses the signal alternation rate at T5 and T10progressively increases as rapidly as the motor is capable of keepingup, until full speed is achieved and the alternation rate reaches asteady state level.

The torque control provided through binary-related inputs at T1-T4 andT6-T9 are coordinated with the velocity control signals provided at T5and T10 such that new signal patterns are applied to T1-T4 and T6-T9each time the signal at their associated terminals T5 and T10 changes.Once the motor is up to speed and copying has commenced, motor movementprocess at a constant rate for the distance determined by the formatselection, and then continues to move the appropriate number of turns toalign with the beginning of the next frame.

Referring now to FIG. 15, a schematic diagram of the circuit forenergizing windings W1 and W3 of y motor 90 is shown. An identicalcircuit with inputs at T6-T10 is utilized to control the energizationfor windings W2 and W4. Input terminals T1, T2, T3 and T4 are connectedrespectively through isolating resistors R1, R2, R3 and R4 to junctionsbetween filter capacitors C1, C2, C3 and C4 and the control terminals ofswitches S1, S2, S3 and S4. Terminals T1, T2, T3 and T4 are alsoconnected respectively through a resistor network R5 to a regulated 5volt DC source to provide further isolation and insure that the inputsignals at T1-T4 successfully actuate their respective switches S1-S4.

Switches S1, S2, S3 and S4 are respectively connected through binaryweighted resistors R6, R7, R8 and R9 to the inverting input of anoperational amplifier 225. The other poles of switches S1-S4 areconnected in common to a regulated 5 volt DC supply through resistorR10, through an RC network 226 to a reference input to operationalamplifier 225, and to an additional filtering capacitor C5. SwitchesS1-S4 and resistors R6-R9 together form a DAC for the digital inputs atT1-T4. An analog signal derived from the instantaneous pattern of inputsignals at T1-T4 is supplied to the negative input of operationalamplifier 225, the output of which is connected through a resistor R11to corresponding poles of two switches S5 and S6 in winding selectorcircuit 203.

Winding selector 203 further comprises a first inverter I1 having itsinput connected to T5 through an isolating and filter network whichcomprises resistors R12 and R13 and capacitor C6, and its outputconnected to a second inverter I2. The outputs of inverters I1 and I2are connected respectively to the controls for switches S5 and S6. Theopposite poles of switches S5 and S6 are connected in turn to amplifiercircuits 205 and 207. The two amplifier circuits are identical, and adescription of one will apply to the other also. Amplifier circuit 205comprises an operational amplifier 227 with its positive input connectedto switch S5, a ground reference at its negative input, appropriatefeedback circuitry, and an output RC circuit 228 connected to the baseof a transistor T1.

Transistor T1 is connected in an energizing circuit for winding W1, withits collector connected to one end of W1 and its emitter groundedthrough resistor R14. Similarly, an output transistor T2 of amplifier207 has its collector connected to one end of winding W3 and its emitterconnected to ground through resistor R15 for energizing W3. Motorwinding current is provided from a 28 volt regulated DC source throughresistor R16 to a common node 228 for W1 and W3. Energizing currentflows through one or the other of W1 and W3, depending upon which oftransistors T1 and T2 is actuated.

The selection of windings and the control over winding current providedby the circuit of FIG. 15 will now be described. Assuming that no signalis applied to terminal T5, inverter I1 produces a positive output whichcloses switch S5, connecting the amplified DAC output to operationalamplifier 227 of amplifying circuit 205. This signal is amplified byoperational amplifier 227 and applied to the base of transistor T1,driving the transistor into conduction by a proportional amount. Thus,as the pattern of input signals at terminals T1-T4 is run through astepping sequence as described above, the winding energizing currenttransmitted by transistor T1 varies in proportion to the analog signalproduced in response to the digital inputs at T1-T4. When the inputenergization sequence for W1 is completed and W3 is ready forenergization, a signal is applied at T5 which removes the positiveoutput from I1 and produces a positive output from I2, thereby turningswitch S6 on and switch S5 off. A control current is then inducedthrough W3 in proportion to the amplified gating signal delivered to thebase of transistor T2. By an appropriate sequencing of digital inputs toT1-T4 (and T6-T9 of FIG. 13) the stepped energizing waveformsillustrated in FIG. 14 may be achieved.

Referring now to FIG. 16, a schematic diagram of the control circuit forx motor 91 is shown. A first input terminal T11 adapted to receive inputsignal from the controller is connected through an isolating andfiltering RC circuit to one input of each of four NAND gates N1, N2, N3and N4. A second input terminal T12 is connected through the isolatingand filter network to the second input of N1, while a third inputterminal T13 is connected through the isolating and filter network tothe second input of N3. The outputs of N1 and N3 are respectivelyconnected to second inputs for N2 and N4. The outputs of N1, N2, N3 andN4 are respectively applied to the base of transistors T3, T4, T5 and T6after inversion by inverters I3, I4, I5 and I6. The collector-emittercircuits of each of these transistors are connected between ground andrespective windings of x motor 91. Energizing current for the motorwindings is provided from a 28 volt regulated DC source throughresistors R17 and R18 to common points for the two pairs of 180° opposedwindings.

In operation, sequential input signal patterns are applied from thecontroller to terminals T11, T12 and T13 at a rate corresponding to thedesired stepping rate. The successive signal patterns are selected suchthat the windings of x motor 91 are energized sequentially, with anoverlap between the energization of adjacent windings if desired. Xmotor 91 is thus controlled to impart a controlled movement to theplaten in the x direction.

Thus, an improved microfiche reader printer has been disclosed whichhelps solve many of the problems of the prior art especially thoserelating to providing the ability to print microfiche of differentformats. It is apparent that various modifications could be made to theexemplary embodiment within the scope of the invention. All such changesand modifications coming within the scope of the appended claimsembraced thereby.

We claim:
 1. In a microfiche reader printer including a light source, aplaten for holding a microfiche in the path of the light from the lightsource, magnifying means in the light path for receiving an image fromthe micro-fiche and magnifying the image, the magnifying meanscomprising a lens support, a plurality of lenses mounted on the lenssupport, a viewing screen, a copier and light directing means foralternatively directing the image from the microfiche through themagnifying means to the viewing screen where the image may be viewed orto the copier where the image may be copied, the improvementcomprising;mounting means for mounting the lens support for movement toposition one of the lenses in the light path, the mounting meanscomprising a pair of parallel gibs, the lens support being slidablymounted between the gibs whereby sliding the lens support between thegibs positions a chosen lens in the light path; sensing means disposedproximate to the lens support for sensing the position of the lenssupport and determining which lens is in the path of light, the sensingmeans comprising a first and a second switch, the lens supportcontacting the first switch when the rightmost lens is in the lightpath, and contacting the second switch when the leftmost lens is in thelight path; platen moving means attached to the platen for moving theplaten and the microfiche on the platen into the light path for copyingsuccessively framed images of the microfiche; and control meansoperatively connected to the platen moving means for controlling theplaten moving means, and reading whether the lens support is contactingthe first switch, the second switch or neither switch and adjusting theplaten moving means for different frame-to-frame movements and foradjusting the speed at which the platen moves to scan the frame beingcopied to compensate for different microfiche formats.
 2. In the readerprinter of claim 1, the improvement further comprising a land area oneach gib, the platen being slidably mounted on the land areas wherebythe distance between the platen on the land areas and the focused lenssupported in the lens support held by the gibs is maintained as aconstant.
 3. In the reader printer of claim 1, the improvement furthercomprising focusing means attached to each lens for adjusting the focusof each lens simultaneously.
 4. In the reader printer of claim 3, theimprovement further comprising the provision of the lenses being mountedin a straight line, each lens being mounted for movement in the lenssupport toward and away from the platen, the focusing means comprising apin extending outwardly from each lens, an eccentric shaft extendingunder each pin for supporting the pins and the lenses at distances fromthe platen, a focus motor, and means for mounting the eccentric shaftfor rotation by the focus motor whereby the focus motor rotates theeccentric shaft and the eccentricity raises and lowers the pins and thelenses with respect to the platen.
 5. A method of duplicating microficheof different formats comprising the steps of:mounting a microfiche in alight path from a light source to a light sensitive surface; selectingthe format of the microfiche and choosing a magnifying lens forinsertion into the light path for magnifying the image from themicrofiche to the copier, the lens being chosen in accordance with theformat of the microfiche; moving the microfiche slowly through the lightpath to scan a frame thereon and moving the light sensitive surfacewhereby the scanned image from the microfiche frame is scanned onto thelight sensitive surface; and moving the microfiche to present successiveframes of the microfiche to the light path to copy the successiveframes; the scanning and the moving of the microfiche from frame toframe being performed at a rate in accordance with the lens chosen andformat selected.
 6. The method as in claim 5 including the step ofmodifying the movement of the microfiche in accordance with thealignment of the frames of the microfiche.
 7. In a reader printer forviewing and copying microfiche, the reader printer including a lightsource, a platen for holding a microfiche in the light path from thelight source, magnifying means in the light path for receiving an imagefrom a frame of the microfiche and magnifying the image, aphotoreceptive surface in the light path for receiving the magnifiedimages from which the image is converted to a visible image for beingcopied on copy paper, means for moving the photoreceptive means throughthe light path whereby the image scans along the photoreceptive surface,drive means attached to the platen for moving the platen to positiondifferent portions of the microfiche in the light path, the drive meansmoving the platen during copying to scan a frame of the microfichethrough the light path, and control means for conrolling the drive meansto drive the platen in a first direction at a format rate such that theframe of the microfiche passes through the light path for the same timethat a portion of the photoreceptive surface corresponding to onedimension of the copy paper passes through the light path, theimprovement comprising:format selecting means connected to the controlmeans for signaling the control means to drive the platen at one of aplurality of predetermined format rates corresponding to the format ofthe microfiche and to the magnifying means selected such that themicrofiche frame of the selected format traverses the light path in apredetermined portion of the time that the portion of the photoreceptivesurface corresponding to the one dimension of the copy paper passesthrough the light path.
 8. In the reader printer of claim 7, theimprovement comprising the magnifying means comprising a plurality oflenses alternatively positionable in the light path, a lens support formounting the lenses to position one of the lenses in the light path,lens switch means mounted in the path of the lens support for signalingthe format selecting means to signal the control means to drive theplaten at a speed corresponding to the format which utilizes the lenspositioned in the light path.
 9. In the reader printer of claim 8 theimprovement further comprising the provision of the lens support holdingthree lenses, the lens switch means comprising a first and secondswitch, means for mounting the first switch such that it is closed whenthe lens support is positioned to locate a first lens in the light pathand means for mounting the second switch such that it is closed when thelens support is positioned to locate a second lens in the light path,the control means including memory means for storing the plurality offormat rates, logic means connected to the memory means for signalingthe control means to read the format rate corresponding to the formatthat utilizes the first lens when the first switch is closed, to readthe format rate corresponding to the format that utilizes the secondlens when the second switch is closed, and to read the format ratecorresponding to the format that utilizes the third lens when both thefirst and second switches are open.
 10. In the reader printer of claim7, the improvement comprising the format selecting means having aplurality of branches, the control means further comprising memory meansfor storing a plurality of format rates for different formats, each ofthe branches being connected to the memory means for reading thedifferent format rates, selector means in each branch for directing thebranch to read a particular format rate from the memory means and logicmeans connected to the format selecting means for choosing one of thebranches to direct the format selecting means to choose the formatassociated with the chosen branch to direct the control means to drivethe drive means at the format rate of the particular format associatedwith the chosen branch.
 11. In the reader printer of claim 10, theimprovement wherein the selector means is a manually positioned switchhaving one position for each format whereby by positioning the selectormeans, each branch will direct the format selecting means to aparticular format.
 12. In the reader printer of claim 11, theimprovement comprising the magnifying means comprising a plurality oflenses alternatively positionable in the light path, a lens support formounting the lenses to position one of the lenses in the light path,lens switch means mounted in the path of the lens support for signalingthe logic means for choosing one of the branches.
 13. In the readerprinter of claim 12, the improvement further comprising the provision ofhaving three branches, the lens support holding three lenses, each lensbeing the proper lens for magnifying microfiche format read by onebranch, the lens switch means comprising a first and second switch,means for mounting the first switch such that it is closed when the lenssupport is positioned to locate a first lens in the light path and meansfor mounting the second switch such that it is closed when the lenssupport is positioned to locate a second lens in the light path, thelogic means signaling the branch for one format corresponding to theformat that utilizes the first lens when the first switch is closed,signaling the branch for a second format corresponding to the formatthat utilizes the second lens when the second switch is closed, andsignaling the third branch for a third format corresponding to theformat that utilizes the third lens when both the first and secondswitches are open.
 14. In the reader printer of claim 11, theimprovement further comprising the memory means storing a nominal formatrate, each branch having rate modifying means connected to the memorymeans for adding an additional rate to the nominal format rate, wherebythe rate modifying means directs the control means at a rate equal tothe sum of the nominal format rate and the additional rate.
 15. In thereader printer of claim 7, the improvement comprising the platen drivemeans being a stepping motor having a plurality of windings, and thecontrol means including means for energizing successive motor windingswith shaped current waveforms to limit jerking of the motor.
 16. In thereader printer of claim 15, the control means including means forenergizing successive motor windings with generally sinusoidally shapedwaveforms.
 17. In the reader printer of claim 15, the control meansincluding a digital-to-analog converter means, means for providing aplurality of sequential signal patterns to the light of thedigital-to-analog converter means for each energization of a motorwinding, circuit means connecting the output of the digital-to-analogconverter means to the motor windings such that energization of awinding progresses in a step fashion corresponding to the sequentialinput signal patterns, and means for directing the motor windingenergizing signals to the motor windings in a desired sequence.
 18. In areader printer for viewing and copying microfiche, the reader printerincluding a light source, a platen for holding a microfiche in the lightpath from the light source, magnifying means in the light path forreceiving an image from a frame of the microfiche and magnifying theimage, a photoreceptive surface in the light path for receiving themagnified images from which the image is converted to a visible imagefor being copied on copy paper, means for moving the photoreceptivesurface through the light path whereby the image scans along thephotoreceptive surface, drive means attached to the platen for movingthe platen to position different portions of the microfiche in the lightpath, the drive means moving the platen during copying to scan a portionof the microfiche through the light path, and control means forcontrolling the drive means to drive the platen in a first direction ata format rate such that the frame of the microfiche passes through thelight path for the same time that a portion of the photoreceptivesurface corresponding to one dimension passes through the light path,the improvement comprising:print initiation means operably connected tothe control means for directing the control means to direct the drivemeans to move the platen so that the frame being copied is moved apredetermined distance from the light path in a second directionopposite the first direction, the predetermined distance being inaccordance with the format of the microfiche; and velocity regulatingmeans operably responsive to the control means and connected to thedrive means to direct the drive means to accelerate the platensubstantially to the format rate in the first direction within saidpredetermined distance, and to thereafter drive the platen at the formatrate as the frame being copied passes through the light path, the formatrate corresponding to the format of the microfiche and to the magnifyingmeans selected.
 19. In the reader printer of claim 18, the improvementcomprising the platen drive means being a stepping motor having apluraity of windings, the velocity regulating means comprising means forenergizing selected motor windings and for adjusting the selection ofmotor windings to be energized, and the control means including meansfor controlling the velocity regulating means to energize successivemotor windings at a progressively increasing rate to accelerate motormovement in the first direction such that the platen is movingsubstantially at the format rate when the frame being copied reaches thelight path.
 20. In the method of printing microfiche wherein a platenholding microfiche is moved in a forward direction to move a frame at ascan rate through a light path in coordination with the movement of aphotoreceptive surface, the improved method comprising the stepsof:positioning a frame such that the first edge of the frame oppositethe direction of travel is in the light path, moving the microfiche in adirection opposite to the forward direction a short distance inaccordance with the format of the mircrofiche, accelerating themicrofiche in the forward direction such that the frame reaches thelight path, moving the microfiche at the scan rate while the frame is inthe light path, and decelerating the microfiche after the edge oppositethe first edge passes through the light path.
 21. In the method of claim20 the improvement further comprising after deceleration, reversing themovement of the microfiche such that a portion of the frame previouslycopied is in the light path, accelerating the microfiche in the forwarddirection to the scan rate before the first edge of the frame adjacentto the frame previously copied enters the light path, moving themicrofiche at the scan rate, and decelerating the microfiche after theedge opposite the first edge of the frame adjacent the frame firstcopied passes through the light path.